Ocean biomass sinking uses macroalgae to remove CO₂ from surface ocean, which in turn enhances the ability of the surface ocean to drawdown atmospheric CO₂. The biomass is sunk into the deep ocean to achieve long-term carbon storage. Here, we specifically consider approaches that do not harvest the biomass before sinking it. This pathway is VCL 1-2, meaning that current quantification capacity may be able to establish net carbon removal occurred, but that very significant uncertainties remain.